Injection nozzle for internalcombustion engines



April `20, 1948., w. von 2,439,832

INJECTION NOZZLE FOR INTERNAL0MBUSTIOII ENGINES Filed June 27. 1939 Inventor y WAK! Voi f' 51 R61 /PILuawl flvwqu'y the nozzle body. A sleeve Patented pr. 20, 1948 INJECTION NOZZLE FOR INTERNAL- COMBUSTION ENGINES Germany; vested in the Attorney General of the United States Application June 27, 1939, Serial No. 281,481 In Germany July 20, 1938 Claims. (Cl. 299-1016) willy voit, stuttgart,

The present invention relates to injection nozzles for internal combustion engines and of the type wherein the nozzle needle is displaced. from a seating surface, in the direction of injection for opening purposes.

The primary objects of the present invention are lto ensure rapid and accurate operation of the nozzle and good atomisation of the fuel.

According to the present invention the needle, beyond its seating surface in the direction of injection, is provided with a cylindrical or substantially cylindrical part, which, during the first part of the opening lift of the needle from its seat on the nozzle body, remains within a complementary part of the nozzle body extending beyond said body seating, so as to substantially or wholly prevent escape of fuel from the nozzle, the dimensions of the cylindrical part of the valve needle in a direction normal to its longitudinal axis of displacement being such that the fuel which is under pressure at the commencement of the opening movement of the needle exerts an additional force on the nozzle seating surface in the opening direction of the needle.

Moreover the needle is constricted between the seating surface and the cylindrical part in such a manner that, when the cylindrical part emerges from the nozzle body end, the outwardly extending peripheral part of the needle constriction, which is adjacent to the cylindrical part, deflects the fuel outwardly in the form of a conical jet.

The invention is more particularly described with reference to the accompanying drawings which show two forms of construction in longitudinal section, by way of example, and in which:

Figure 1 is a section through one form of nozzle and its holder.

Figure 2 is a large scale section through the injection end of the nozzle of Figure l when in the closed position.

Figure 3 is a corresponding section of the nozzle fully open.

Figures 4- and 5 respectively illustrate a modied form of construction, in closed and open positions.

A nozzle holder I is secured by a cap nut 2 to a. nozzle body 3 having an axial bore t which has a wide part at its outer end, and in which a displaceable nozzle needle 5 is provided, the needle 5 at its injection end having a seating surface 6 adapted to limit the displacement of the needle in the closing direction. A closure spring 1 is provided for forcing the seat 6 of the needle 5 lightly against a complementary shoulder 8 of 9a combined with a 2 spring collar 9 limits the degree of opening of the needle. In the direction of injection the nozzle needle 5 has an extension beyond the seating 6 which extension tapers inwardly inthe manner of a truncated cone and then slopes outwards again, the surfaces of the constriction being indicated by the numerals Il and l2 with the latter presenting a greater component in a direction normal to the axis of the needle than the former. The nozzle body 3, in the region of the opening thereof, is provided with an annular groove, one inclined bounding surface 8a of which forms an extension of the nozzle seat 8, and the oppositely inclined bounding surface of which is` indicated by the numeral i3.

It will be appreciated that the internal periphery of the nozzle body and the external periphery of the nozzle needle, and the limit of opening displacement of the needle are such that when the needle is fully open (Figure 3), the cross section of the fue1 path through the nozzle is substantially uniform throughout its length.

The outer end of the extension of the needle is designed as a. cylindrical part li which, when the needle is in the closed position projects a small distance into the complementary cylindrical part of the bore 4 of the nozzle body 3.

The operation of the nozzle is as follows:

As soon as a hydraulic force operating in the opening direction of displacement of the needle exceeds the force applied by the spring l, the seat 6 of the nozzle needle is raised from the body seating surface 8. Since at the commencement of this movement the cylindrical extension Hl of the needle 5 still remains within the bore of the nozzle body 3, thus preventing, or at least greatly reducing the passage of fue1 through the exit orifice of the nozzle. the pressure of the fuel is exerted in the opening direction of the entire nozzle seating surface, so that the total surface affected bythe fuel pressure is considerably increased. -As a result, immediately after the commencement of the opening lift of the needle from its seat, the displacement of the needle is accelerated in the opening direction whereby it is swiftly and effectively brought into the fully open position.

Thev needle surfaces H, l2, and the nozzle surfaces Ba. I3, serve as guide and rebound surfaces which direct the fuel outwardly through the mouth of the' nozzle in the form of a divergent conical jet.

The modified form of construction shown in Figures 4 and 5 diiers from the rst in that the end lia of the nozzle bore, between the exit orifice ofthenozziebodytandtheseatingsurfacel thereof is cylindrical. Moreover the needle is p vided with guide and rebound suifaces in the rm of a pintle Il, sloping conically outwards from the cylindrical part Il, then again sharply inwards. In all open positions of the needle, the fuel impinges on the upper inclined surface I8 of the pintle and consequently diverges in the form of a conical iet. In this form of construction care must be taken that the design and slope of the surfaces il and l2, and particularly the width and slope of the surface i12 is such that A these surfaces direct the fuel on the surface i9.

I declare that what I claim is:

1. An injection nozzle for internal combustion engines comprising a nomle body having a bore therein of differential width longitudinally and a needle displaceable in said body toward the exit orice thereof for opening purposes, said bore and needle being provided with cooperating conical valve seating surfaces. said bore having a cylindrical portion, beyond its seating surface, providing the exit orifice of said nozzle body, the said needle beyond its seating surface in the body bore and in the direction of fuel injection being provided with a substantially cylindrical portion which during the first portion of the opening lift of the needle from its seat on the nozzle body remains within the complementary cylindrical portion of the nozzle bo@ so as to prevent escape of fuel from the nozzle but which finally emerges entirely from the cylindrical portion forming the exit orince of said nozzle body to permit flow of fuel from said oriilce, said cylindrical portion of said -needle having a diameter at least as great as the largest diameter of said valve seating surface of .said `needle and arranged to form an annular shoulder whereby fuel under pressure delivered to said bore at the commencement of the needle opening movement exerts an additional force on said needle in the opening direction thereof as long as the cylindrical portion of said needle remains in said complementary cylindrical portion of said nozzle body, said bore adjacent' its seating surface having a diameter larger than the largest diameter of the valve seating surface of said needle and having a wall surface at an angle to the conical valve seating surface of the bore to deflect fuel flowing past said seating surface, said needle having a constricted portion between its seating surface and its cylindrical portion to form with said deecting wall surface an annular channel for fuel, said constricted portion being formed to provide a conical surface which in the open position of the needle at least partly emerges from the cylindrical portion forming-the exit orlce of said nozvle body whereby the dow of fuel is directed outwardly awayfromtheaxisoftheneedle.

r 2. An iniection nozzle as set out in claim l. in which the conical valve seating surface of said noazle body is continued, in the direction of inlectlon, until it meets said deflecting wall surface. which is also conical, to provide the maximum diameter portionofsaid bore.

3. An injection nozzle as setfout in claim 1, in which the constricted portion of said needle is formed by oppositely inclined conical surfaces.

4. An'iniection nozzle as set out in claim 1, in which the constricted portion of said needle is formed by oppositely inclined conical surfaces, and the valve seating surface and the deflecting wall surface of said nozzle bore are formed by `oppositely inclined conical surfaces whereby length is provided for ilow of fuel between the .surfaces of said needle and the surfaces of said the nozzle bore.

WILLY VOIT.

REFERENCES CITED The following references are of record in the nie of this patent:

UNITED STATES PATENTS Number Name Date 2,077,938 Kuttner Apr. 20, 1937 2,017,028 Heinrich et al. Oct. 8, 1935 2,172,556 Edwards Sept. 12,1939 1,737,155 Hewitt Nov. 26, 1929 2,143,429 Nelson ---r Jan. 31, 1939 2,154,875 Streby Apr. 18, 1939 2,192,803 Purdy Mar. 5, 1949 2,210,783 Tabh et al. Aug. 6, 1940 2,263,197 Tabb et al. Nov. 18, 1941 FOREIGN PATENTS Numlie; 7 Country Date 49 3 Germany June 14, 1930 218,593 Germany Feb. 4, 1910 `532,013 Germany Aug. 22, 1931 

